Archive for the ‘water’ Category

This is the time of the year when you do a round up of what went by but perhaps more importantly what can occur in the near future. Here then is a wish list for 2013 vis-à-vis water in all its forms.

We will all become water warriors – Let us imagine an active citizenry engaged daily in wise water use, water conservation, solid waste management such that water is not wasted or the environment polluted by any one of their actions. It is not too difficult and as Gandhiji said ‘Be the change you want to see in the world’.

A blue rainwater filter

The institution will achieve universal coverage – Each and every home in the city will have a water and sanitation connection, be it ‘pukka’ or ‘kutcha’ , be it legal or not , be it in a slum or in a posh neighbourhood . Difficult? Not really if each ward of the city measures the connections achieved on a monthly basis.

The tanks in the city will ALL be revived – That every neighbourhood will have a clean expanse of water body to gaze at, to walk around, and to see the birds and that it will be a community property resource for all to enjoy.

Tanks need revitalization

The storm-water drains in the city will be cleaned – sewage treatment plants distributed all across the city will clean all the waste-water picked up by an efficient sewage line network. The treated waste water will be let into wetlands which abut tanks and thence will fill the water body to the brim. Only rainwater from roads will flow in the storm drains.

The rainwater in storm-water drains will be recharged into the aquifer through a series of recharge wells

Storm-water recharges an aquifer through a recharge well

Rainwater harvesting in every home – Rain barrels will dot every home and every apartment, collecting rainwater for supplementary use. Those buildings which cannot will collect rainwater in sumps or make recharge wells to allow it to go into the aquifer replenishing it.

Bore-wells– The mad drilling of individual bore-wells will stop, instead a sharing of ground-waters through community bore-wells will happen. People will instead contribute to keeping these bore-wells recharged through individual point recharge structures in storm water drains and within the plot.

Every bore-well will be recharged with clean, filtered rainwater

Recharging a defunct bore-well with rainwater

Septic tanks and pit toilets – those buildings not connected to the sewage lines will have well designed septic tanks and pit toilets emptied at regular intervals by the mechanical sludge removers called Honey-suckers. This removed sludge will be scientifically composted and reused as fertilizer to revitalize soils all across the city.

Schools, colleges, anganwadis and hospitals – Special attention will be paid to these institutions where the young and the vulnerable occupy. Water and sanitation will be available 24/7 thus ensuring health, hygiene and water literacy.

Parks and playgrounds – Most of the parks will become tree based instead of the water guzzling lawn based parks. Each park will harvest its own rainwater correctly by linking catchment, conveyance and recharge properly.

Here is wishing us to become a water sensitive city in this year alone.’ You may say I’m a dreamer but I’m not the only one’ as one of the Beatles has famously said.

Huge blocks of flats in cities can provide supplementary water requirement, manage floods and reduce pollution of the environment

Simple techniques: Storing rain and rooftop water in apartments has now become easy

Apartments are mushrooming all over our cities with the boom in the housing sector. These apartments place a huge demand on the infrastructure of the city, be it water, sewerage, stormwater drains or roads. By designing systems carefully and investing in sustainable technologies, apartments can provide supplementary water requirement, manage floods and reduce pollution of the environment.

Consider this large set of apartments in Koramangala which has eight blocks. Six of them have a roof area of 1,000 square metres and two of them have a roof area of 2,000 square metres. The flats are to a large extent dependent on borewells for their water requirement. Car washing in the basement is a significant water consumer. The apartment block wanted to implement a rainwater harvesting scheme to get enough water for the car washing purpose.

Rooftops are ideal catchments for rainwater. If they are clean and allow rainwater to runoff to the down pipes, it is more than enough. In these apartments, the rooftops were ideal catchments.

Down pipes bring the rainwater to the stormwater drains. They should ideally be separated from the sewage and grey water lines. The National Building Code recommends that rainwater pipes be separate from other waste water pipes to prevent overflowing manholes and also to prevent overload of the sewage treatment plants. Many apartments, due to faulty design, tend to merge the two. Here the case was exactly this. The rainwater pipes therefore had to be de-linked from the sewage pipes.

The down pipes were now connected to large rain barrels of 10,000 litre capacity in the basement. The harvested rainwater is to be used for car washing, gardening and other non-potable use. A total of 1.75 million litres of water annually is expected to be harvested from one block alone. Similarly, the collection process has been expanded to another block and in a phased manner will cover all blocks.

When the entire rooftop rainwater collection is put in place, the apartment will harvest 8.75 million litres annually from the rooftops alone.

Stormwater

The stormwater drainage network was found full of garbage and dirt. Regular cleaning will ensure that a substantial amount of storm water too becomes harvestable either to be stored or to be recharged into the aquifer.

Another set of apartments on Bannerghatta Road had not only kept the rooftop clean but also had ensured that the rainwater pipes were kept separate from sewage lines, connected and brought to one place. With a filter, the collection of rooftop rainwater into a 20,000 litre tank became very easy. When the rainwater quality was tested, it was actually found to be of potable standards. This apartment therefore decided to connect the rainwater tank to the regular sump and use the combined water for all purposes. With a 20,000 litre rainwater collection sump and a recharge well for the overflow, the apartment now collects or recharges 550,000 litres of rainwater annually.

Apartments can supplement their water requirement and increase the life of their borewells through smart designs and rainwater harvesting. They can also prevent urban floods. A system of clear guidelines and implementation skill will increase the sustainability of Bangalore’s waters. In this path is water wisdom.

California already mandates a white roof for its buildings but if it makes energy sense and economic sense, white insulating and reflective roofs should become a matter of choice rather than being imposed through legislation.

If you ask Hashem Akbari the one thing that he would do to save the planet from the ill-effects of global warming, he would say paint the roofs of the homes of 100 of the world’s largest cities white and change the road surface to a light colour. Who is Hashem Akbari? He is a physicist and part of the heat island group at Ernesto Orlando Lawrence Berkeley National Laboratory and was presenting a paper at the fifth annual climate change conference in Sacramento, California, on September 9, 2008. (His website is at http://heatisland.lbl.gov/ for those who need more info).

White reflective roofs

It is well known that roofs are the largest heat gainers in buildings and also that if the roofs are painted white they would reflect a large percentage of the incident solar radiation, especially the infra red radiation, away and keep the building cooler. A good reflective white paint brand like the Australian paint called Insultec, claims to reradiate 95 per cent of the infra red rays and 85 per cent of the ultra violet rays, thus reducing the heat load inside the building by 30 per cent. This can reduce air-conditioning costs considerably in buildings. These insulating paints also have the advantage of being water proof and prevent the conduction of heat also.

They can normally be applied on any surface including RCC roof surface, tiles, asbestos sheets and even on poly-coated sheets. Costs are supposed to range from Rs. 40 to Rs. 50 a square foot .

While at an individual building level there is a saving in electricity consumption and having a cooler building, Hashem Akbari adds it up by arguing that lower power consumption means lesser requirement from power plants and therefore lesser generation of CO2 and NOx by the power plants, therefore contributing to the lessening of global warming. Each building can therefore contribute in its own way to lesser emissions from power plants.

Cut in emissions

A 1000 sq. ft. of roof area, a typical roof on an average 30 x 40 site in Bengaluru, painted white can offset 10 metric tonnes of carbon dioxide emissions as compared to a dark roof, say with tiles.

Consider this: 44 metric gigatons of carbon dioxide and other green house gases would be offset if the world’s 100 largest cities converted their roofs to white and made their roads lighter.

California already mandates a white roof for its buildings but if it makes energy sense and economic sense white insulating and reflective roofs should become a matter of choice rather than being imposed through legislation. Asphalted and tarred roads are dark in colour and absorb heat as any two-wheel driver will tell you during summer time. Roads which are dark and blacktopped can also be changed to lighter coloured and more reflective concrete roads.

Since roads make up 25 to 35 per cent of a layout or a city, changing their colour to lighter shades and increasing their reflectivity will cool the immediate surroundings by 2 to 3 degrees Celsius and also contribute to power savings. The importance of avenue plantations and tree shading on both roads and buildings cannot be re-emphasised.

Not only does it contribute to the micro-environment and biodiversity but there is increasing evidence that on a larger scale this can reduce global warming.

Good reflective and insulating paints on the roofs also have another advantage on roof and water. They can be cleaned easily. Their runoff coefficient — the amount of rain that runoff during rains — is higher; therefore, more rainwater can be harvested from such roofs. When the paints are made of inert material and are non-toxic the run-off water quality is also improved and this rainwater can be harvested and even used for drinking.

Thinking smart about roofs helps the building, the earth and water. The roof above your head not only protects the individuals inside but can contribute to solve problems related to water, energy and global warming.

Water, water everywhere…planners, institutions and individuals can take several steps to mitigate the physical and economic impact of urban flooding, says S. VISHWANATH

— Photo: K. Murali Kumar The deluge: The state of affairs in an upmarket villa after a lake breached on the Whitefield-Hoskote Road.

A series of flooding events across Bengaluru has brought into sharp focus the need for better management of rain. Though nothing on the scale of the Kosi floods yet, it has caused severe economic and physical damage to the city and left many psychologically scarred. The coming of the rains is looked at with trepidation and newer areas of the city seem to be affected every time it rains.

Several interesting facts emerge around urban floods. In Bengaluru, it is clear that it is rain which causes the floods unlike, say, a city like Patna where rain could cause the Ganga to swell and flood the city. Surprisingly, recent evidence suggests that it rains more in the city and slightly downwind than in the regional rural periphery.

This is according to a study by NASA scientist Marshal Shepherd. The urban heat island effect, where cities are warmer than their surroundings and which causes the build-up of rain clouds on the city; pollution, which allows rain to coalesce around dust and oil particles; and the wind-break effect of cities, which causes the clouds to discharge on the cities, all seem to contribute to this phenomena. Bengaluru needs to prepare for more rain than average and higher intensity rains at the same time.

Cities also increase runoff as more and more soft agricultural and fallow areas get built upon or paved. From a small well-mulched site, hardly 10 per cent of the rain falling will runoff as storm water. However, build a house on the same site and pretty much 90 per cent of the rain falling will runoff as storm water. Buildings increase runoff tremendously in the Bengaluru context and the storm water drains have to cope with this increase.

Waste management

Solid waste management is crucial to flood management since most of the uncollected garbage will end up in the lowest area, usually the storm water drains, choking them and reducing their ability to carry storm water out.

Tanks and lakes which collected surplus water and recharged the groundwater or dissipated it slowly are on the decline. These are built up, like the ISRO headquarters built on an old tank bed. They then become prone to flooding or transfer the flood problem downstream.

The network of tanks and the valleys and drains connecting them are in a bad state of management with encroachments on several of them. With no institutional approach to manage the tanks and the valleys, little is done except during the flood event itself to ensure that the channels flow freely and that the tanks are not encroached upon. Traditional storm water management techniques simply collect the rain water and funnel it across the city downstream. Newer methods combine traditional approaches with new ones such as Sustainable Drainage Systems (SUDS). It employs a range of natural processes to purify urban runoff. Removal of sediment, bio-filtration, biodegradation and water uptake by plants all help to remove pollutants. Vulnerability maps of areas prone to flooding need to be prepared for citizens to become aware of the choice they make for where they live.

Rainwater harvesting

Even as the Government is working towards making RWH mandatory in the coming days for the city, the system has one of the best potentials to replenish ground water, improve its quality, provide supplementary water for domestic requirements and mitigate flooding. If every building in Bengaluru can store or recharge 60 mm of rain in a single day it should be possible to mitigate the effect of almost every flood except the rare. This means that a 100 square metre roof area will need to store or recharge 6,000 litres of water. Zones with the best possible recharge and zones with the best possible storage need to be identified in the city and steps taken to encourage people to go in for rainwater harvesting.

A recharge well of 3 feet diameter and about 20 feet depth can send in up to 12,000 litres of water into the ground in a single day, provided lithological conditions are favourable. The city needs many such recharge wells in the catchment area of critical flood zones to detain flood waters and top up the aquifers instead of surface flow flooding.

At the broader scale, tanks and lakes need to be networked and managed as retention and detention structures. With rainfall prediction accuracy being developed, tanks have to be linked to catchments and kept ready to hold the maximum water to dampen peak storm events. A deslited tank in Bengaluru can recharge up to 11 mm of water every day while an undesilted one can recharge hardly 1 mm. Desilted tanks can recharge aquifers quickly, lower the surface water levels and be in a position to function as flood mitigators. Full tanks are not good at dampening floods.

Flood insurance

In Europe, urban flood research has been driven by insurance companies who want to understand risks associated with floods and plan premiums accordingly. This sector has yet to mature in India but taking flood insurance is a wise step especially if your car has been found floating in the basement after a rain. Good advice comes from ICICI-Lombard on its website on what to do after a flood. It starts by saying that you should not return home till the authorities declare it safe to go back. Then the steps recommended are: turn off electricity and gas, make sure the water and food you consume are safe, stay healthy, call your insurance agent, take photographs and videographs of the damage caused and finally take care of yourself and family. Wise words, indeed, and this is water wisdom when it relates to urban floods.

Think of any new development coming up in a city and the first consideration would be the source of water. Isn’t it difficult to imagine that till the 1960s the borewell as a technology did not exist in India?

It is difficult to imagine that till the 1960s, the borewell as a technology did not exist in India; that it required persuasion to get decision makers and farmers to appreciate the fact that lots of water could come up through a four-and-a-half-inch diameter pipe which went deep into the ground.

Now, India survives because of this pipe which became a six-inch pipe and now is also a eight-inch pipe. First, the pipe went 80 feet down; now it goes 1,500 feet in some places and provides for Karnataka survival water for upwards of 45,000 habitations. And almost all cities depend to varying degrees on groundwater.

Think of any building coming up in a city and the first consideration of the owner or the developer would be a source of water for the development of the site. Usually, the question is where should I dig a borewell and how do I go about it. A dowser is usually more popular than a hydro-geologist.

Ignorance

People’s faith in faith is more than in science, but if you get a ‘2-in-1’, a hydro-geologist who also wields a pendulum or a fork, the better. This is the abysmal state of the science of groundwater in our country and the complete ignorance that we display towards understanding it scientifically.

Large-scale utility providers of water such as the Bangalore Water Supply and Sewerage Board do not have a single hydro-geologist working for them. Universities and colleges do not have quality training programme and there is virtually no skill upgradation centre.

So, what is the advice to a borewell digger? Get hold of a good hydro-geologist and get him to do a detailed analysis of your site. He should be able to give you a good soil and lithological profile. Keep that map. He should also be able to suggest potential points of drilling and the depth at which water will likely become available. Approximate depths of casing required and how to go about selecting the right pump should also come from him.

Do not forget to get suggestions on recharge points and some tips on maintaining your borewell.

When you drill the borewell finally, keep the records carefully. Even failed borewells have tremendous information, so keep the knowledge on these points carefully mapped on a plan.

Monitor

Continuously monitor the quality of your borewell water and measure the summer and the rainy season discharge quantities. Develop a maintenance system for all the appurtenances such as the pump and the electrical systems. An annual cleaning of the borewells is also recommended. Fix a water meter and a separate electric meter for your borewell. This will give valuable information.

Understanding the role of groundwater, taking care of the aquifer quantity and quality and developing the science behind groundwater will be crucial to the sustainable availability of water. Each one of us has a role to play if we have a borewell. In this science lies water wisdom.

Cities and city utilities all across India are looking for ways to save water as this critical resource becomes scarce or threatens to run out. Getting the consumers is seen as an important way to reduce consumption. While appealing to their good conscience is a nice way it hardly works. The best way is economic incentives since money talks. What then should be the approach to incentivize water conservation? Here is a strategy for Bangalore admittedly starting with certain advantages

Bangalore has every connection metered and an increasing block tariff due to historic reasons. The tariff however heavily subsidizes domestic water with perverse incentives. For example with a production cost of Rs. 24/- a kilo-litre (Rs 18 /- a kilolitre plus losses in the system of 37%) a household with a domestic connection which consumes 25,000 litres of water per month gets a subsidy of Rs. 400 /- approximately per month.

The current increasing block tariff slab for a domestic connection in Bangalore works in this fashion

Incentives for water conservation: On the other hand if a household harvests rainwater and does not draw a drop of water from the BWSSB it still gets a bill of Rs. 48 /- covering the first slab. While the household has SAVED the BWSSB Rs. 400 /- it has been penalized with a minimum bill.

How then to devise a pricing strategy to include rainwater or recycled water as an incentive for households to consume instead of BWSSB water?

Let us assume an average standard demand of 135 litres per person per day and an average family size of 4. Monthly demand would therefore be 135 x 4 x 30 = 16,200 litres say 16 kilo-litres. This is a reasonable quantity of water a family is expected to consume in a month. Anything less than this shows frugality in water use, conservation and perhaps rainwater harvesting and water recycling, all deeds that the city needs to reward the family for.

Reward:

How should the reward go to the family?

Let us assume that the family has only used 5 kilolitre of water in a month. Consumption below expected normal demand of 16 kilolitre is 16 – 5 = 11 KL .

Subsidy that the family would have got from the BWSSB at 16 KL of consumption = 8 x 18 + 8 x 15 = Rs264 /-

Let us define an incentive fund of Rs 18 /-(the gross production cost of water to the BWSSB) minus Rs 9 /- ( a reasonable tariff for the lowest slab in the coming days ) = Rs 9/- per kilolitre

So for every kilo-litre less than 16 kilolitres consumed by a family in a month it will get that saving of water in KL into Rs 9/- as an incentive amount to be set off against future bills.

The family saves Rs 99/- the BWSSB saves Rs 165/- a win- win situation for both and for the city too in terms of the waters released to be supplied to others which is 11 KL per month.

Now if this were to be applied all across the city to the nearly 6 lakh connections it would not require anything except an additional row in the water bill. No extra administrative costs would also be expected and most importantly the subsidy would be a reward for those who showed good behaviour.

Compare this to a rebate in property tax which is given in some cities for rainwater harvesting which rewards a house owner and notrentor and also does not send any signal for wise water use and one sees the need for such bold moves on the part of cities and city utilities.

A hard look at water tariffs and a revision is overdue as is the need to economically incentivize the wise water user. Will such water wisdom dawn on us?